Mounting navigation equipment on aluminium alloy vessels (AMG, D16T) has always been considered more challenging than installing fiberglass or PVC floating craft. Metal acts as a Faraday screen, blocking the weak ultrasonic signals that emit sounderThat is why the owners of "aluminium" often wonder: how to properly fix and configure the device brand LowranceSo it's a real underwater world, not a chaotic noise?
Unlike plastic, aluminum conducts electricity, which creates additional short-circuit risks and requires a special approach to power management. Incorrect installation can lead not only to inoperability of the device, but also to electrochemical corrosion of the boat hull. In this article, we will discuss the technical nuances that will allow you to get a high-quality signal and reliable navigation system in all conditions.
You don't have to be a professional electrician to do this work yourself, but you have to have basic tool skills and follow the instructions clearly. We'll look at the location selection, the attachment methods, the interference protection and the final setup to make sure that you have a good choice of location. Lowrance Hook or HDS It worked with maximum efficiency.
Selection of location and method of attachment of the sensor
The first and most critical step is to determine the installation site. There are two main ways to do this for aluminum boats: sensing (In-Hull) which is mounted inside the housing, or installation remote-sensor The first option is more aesthetically and reliably, because it eliminates the risk of damage during mooring, but requires drilling the hull.
If you want to make a cut, you need to find a place with a flat bottom surface, where there are no stiff edges, welds or rivets, and the surface should be perfectly smooth, so that there are no air bubbles between the bottom of the boat and the emitter. It is critical to use a special gel aggregateSince regular silicone can dry or bubble, completely blocking the signal.
The situation is different with transom mounting. Aluminum transom often has complex geometry. You'll need a special bracket that will provide a vertical position of the sensor when the boat is moving. You don't have to rely on the regular plastic mounts that come with the kit - at high speeds, an aluminum boat creates strong turbulence, and flimsy plastic can not withstand.
It is important to consider the angle of entry of the beam. The sensor must look downwards, perpendicular to the surface of the water. Any deviation will lead to loss of contact with the bottom on the move or the appearance of "dead zones" on the sides. Aluminum boats with a kilted bottom often require the manufacture of a personal pad.
Specifics of working with aluminum housing
Aluminum is a non-ferrous metal that, when paired with other metals (copper, brass, stainless steel), creates current. If you just screw the sensor or use the wrong sealant, after a few seasons you run the risk of end-to-end corrosion. So all fasteners must be made from stainless steel Titanium and contact with water are minimized.
Pay special attention to surface preparation. Before inserting the aluminum sensor, you need to clean with fine sandpaper to a metallic shine, degrease with acetone and only then apply a contact gel. The presence of an oxide film on aluminum can worsen the heat sink and adhesion of the sealant.
⚠️ Warning: Never use copper wires or brass bolts to attach water-contact elements directly to the aluminum board, which will trigger an irreversible process of electrochemical corrosion that will destroy the boat hull in one season.
Another nuance is the thickness of the metal, and the ultrasonic signal passes through thin aluminum (up to 6-8 mm) with little or no loss, but if your boat has a reinforced bottom or a double side, the signal power may not be enough, and in such cases it is better not to risk it and choose an external installation.
What is a galvanic junction?
Galvanic interchange is a method of transmitting a signal or energy between two circuits without electrical contact. In the context of sonars, this prevents wandering currents from the motor or shore outlet from entering the boat hull, saving the metal from corrosion.
Protection against electrical interference
An aluminum boat is often equipped with a powerful outboard motor, which is a source of strong electromagnetic fields: the generator, the ignition system (especially if it is a two-stroke engine), the pumps and lighting equipment create “electromagnetic noise” that is directed on the sounder’s power wires and distorts the picture on the screen.
To minimize interference, you need to use shielded cables. Lowrance It doesn't have a high-quality braid, it should be replaced or additionally shielded, and lay the power wires and signal cables as far away from the power lines of the motor and the battery as possible.
- 🔌 Use separate terminals to connect the sonar, do not hang it on the same point with navigation lights or pump.
- 🛡️ Lay the cable along the side, fixing it with plastic clamps, avoiding hinges and saggings, where moisture can accumulate.
- ⚡ Install ferrite filters (rings) on the power cable closer to the sonar connector to cut off high-frequency tips.
The quality of the "mass" (minus wire) is crucial. Poor mass contact causes the sonar body to become the antenna itself, catching all the interference, and clear the contact to pure metal before screwing the terminal.
If you have vertical bands or chaotic dots on your sonar screen, try temporarily turning off all the other appliances on board. If the noise is gone, look for the source of interference among them.
Connection scheme and catering
Echo sonar connection Lowrance Standard color markings for wires are red plus (+), black minus (-). For aluminum boats, it is critical to protect the circuit not only from short circuits, but also from the voltage surges that can occur when starting the engine.
It is recommended to power the device directly from the battery through a separate fuse with a nominal value of 3-5 Ampere. Laying the wire across the board requires the use of a corrugated tube to protect against rubbing on the sharp edges of aluminum frames or zygomatic joints.
Below is a table of recommended parameters for connecting different models:
| Lowrance model | Supply voltage (B) | Recommended safety lock (A) | Cable cross-section (mm2) |
|---|---|---|---|
| Hook Reveal 5 | 12-24 | 3 | 0.75 - 1.5 |
| HDS-7 Live | 12-24 | 5 | 1.5 - 2.5 |
| Elite FS 9 | 12-24 | 5 | 1.5 - 2.5 |
| HDS-12 Live | 12-24 | 10 | 2.5 - 4.0 |
All connections outside the hazelnuts must be sealed. Use adhesive shrink tubes or specialized sea connectors. The usual insulation on an aluminum boat will quickly become unusable due to vibration and humidity.
☑️ Pre-introducement check
Installation of the in-hull sensor (In-hull)
If you choose to install the sensor inside the body, prepare the location carefully. Draw the sensor outline with a marker. Cut the hole or prepare the site so that the sensor is attached to the entire surface. For epoxy resins and gels, cleanliness is important.
Apply a special ultrasonic gel (or a mixture of epoxy without a hardener if you use the "epoxy landing" method, although the gel is preferable for removable structures). Press the sensor, excluding air bubbles. The air bubble is 100% signal loss, since ultrasound does not pass through the solid-gas boundary.
Once fixed, let the composition polymerize according to the instructions. Don't rush the boat into the water. After drying, check the reliability of the mounting, slightly wiggling the sensor (without fanaticism). The wire inside the boat must also be reliably fixed so that the vibration of the motor does not shake the place of sticking.
⚠️ Note: When drilling holes under the cable, use only special drills on aluminum and be sure to remove the "shaft" (sharp edges) from the back of the hole so that the cable does not cut with vibration.
System setup and calibration
After you physically install it and you first turn it on, you have to adjust it, and the aluminum bottom gives you a very clear, but sometimes very powerful signal that can blind the receiver in shallow water. Go to the sounder settings menu.
First, choose the right frequency. For aluminum boats with cut-in sensors, frequency is often optimal. 50 kHz or 83 kHzBecause they penetrate the water column better and are less sensitive to air bubbles under the bottom than high frequencies, however, for a detailed look at the structure of the bottom and fish, it is better to switch to the following: High CHIRP.
- 🎛️ Adjust the sensitivity: Reduce it until the “noise” in the water column disappears, but the bottom remained clear.
- 🌊 Set the Range: Set the automatic mode or manually set the depth corresponding to your body of water.
- 🚤 Turn on the “Boat in motion” mode, if any, to compensate for the speed of the signal.
The right sensitivity setting is more important than the maximum power, and the oversensitivity on an aluminum boat turns the screen into a mush of interference.
Do a test swim in a familiar area of the reservoir. Compare the sounder to the actual depth you know from navigation charts or measurements. If the readings are floating, check again the density of the sensor and the absence of air pockets.
Frequently Asked Questions (FAQ)
Can I attach the Lowrance sonar sensor to an aluminum transom on the outside?
Yes, this is the most common and easiest way, and the key is to use a bracket that allows you to adjust the depth of the dive and the angle of inclination to compensate for the keeliness of the bottom of the aluminum boat.
Why does the sonar show "porridge" at high speed?
It's likely that air (cavitation) is coming under the sensor because of turbulence, try lowering the sensor deeper or changing the angle of the sensor, and check if the sensor is too sensitive.
Do I need a separate battery for a sonar on a small boat?
A separate battery is not required if the main battery is in good working order and has sufficient capacity, but connection through a separate fuse and the use of quality wires is strictly necessary to protect against interference.
Which gel is better to use for a cut-in sensor?
It is best to use specialized gels from manufacturers of sonar (Garmin, Lowrance, Raymarine) or special epoxy compounds for ultrasonic sensors. Conventional plumbing silicone is not suitable.